The present invention relates to a tilting stick control device as well as an aircraft flight control system comprising such a control device.
Although not exclusively, it applies more particularly to aircraft piloting systems and it will be more specially described hereafter with reference to such an application, it of course being understood that no limitation of the scope of the invention can result therefrom.
Numerous machines, such as aircraft, helicopters, tanks, public works machines, etc. . . , are provided with a set of controlled elements which can be operated from one or other of two pairs command stations, controlled by two separate operators, called pilot and copilot in the case of vehicles, and each equipped with a stick type control member, articulated so as to pivot in any direction. These control members are connected to said members to be controlled and are coupled together so that each of said operators has available the set of controls for said members to be controlled and so that voluntary tilting by direct operation of one of said control members by an operator causes an identical induced tilting in the same direction of the other.
Up to present, the transmission of the control orders between a stick actuated by an operator and a device to be controlled has taken place mechanically so that said sticks were of relatively large sizes and capable of withstanding and transmitting high mechanical forces. Such sticks were therefore provided so as to be disposed in front of said operators, held in both hands by each operator and actuated by his forearm, the amplitude and intensity of their movements being conditioned by the resistances to overcome for operating the mechanical controls.
However, mechanical controls are more and more often replaced by electric controls which have numerous advantages, for example in so far as the weight, size, maintenance, accommodation of complex control laws etc. . . are concerned. The result is that said sticks are connected to and associated with electric sensors which detect the variations of position of said sticks and which control electric controls actuating said controlled devices depending on the indications of said sensors. Under these conditions, said sticks only transmit very small forces and their dimensions and mechanical strength may be considerably reduced. Thus, small size sticks have been designed and used, called ministicks which can be held and actuated by one hand by an operator.
In addition to the above advantages concerning the use of electric controls, such ministicks free the space in front of the operators for optimizing the grouping together of other controls in front of them, so that each ministick is disposed laterally with respect to said operators. In addition, particularly when the two command stations of the operators are parallel (which is generally the case in a vehicle in which said stations are disposed facing forwards), in order to comply with the symmetry of the machine with respect to an axis passing between said stations, one of the ministicks is dispose on the left of the left-hand operator and the other on the right of the right-hand operator. In such a case, the left-hand operator therefore holds the associated ministick with his left hand, whereas the right-hand operator holds his with his right hand.
When such known ministicks are applied to the control of an aircraft, front to rear and rear to front tilting is used for controlling pitching (elevation) whereas the left to right and right to left tilting is used for controlling the aircraft in rolling. However, no other movement of the ministick is available for yaw control (direction). Therefore, in known aircraft with electric flight control, the yaw control remains mechanical, using a conventional rudder bar.